Martin MSP4100SW SP Phosphor Bronze Acoustic Guitar Strings， Light， 12-54<div style="text-align: left;"><strong>[Product Information]</strong><ul><li><span class="a-list-item"> Light: .012， .016， .025， .032， .042， .054 </span></li><li><span class="a-list-item"> Phosphor bronze </span></li><li><span class="a-list-item"> Made with the highest quality bronzed steel core wire and phosphor bronze wrap wire </span></li><li><span class="a-list-item"> Our SP line of strings stands up to rigorous practice and performance schedules to deliver consistent true tone that you can count on song after song </span></li></ul></div><img src="http://ecx.images-amazon.com/images/I/61AT-VsemNL.jpg" noproxy>